interesting subject in these up-coming times... I am myself thinking about it and can't wait until the winter time! :)
I'm glad to see that other people support the Joutsen option since that was my initial thought. I think that if it is really cold, you don't have a better option.
However, I was thinking to share my own sleeping system for such temperatures. It might help you to make your own decision. Here it is:
- Joutsen 900 QTM (450g of down first class -don't exactly know the CUIN but close to 800 cuin EU standard I believe). T° confort about 0°C / -2°C by experience (extreme -20°)
- Jack-R-Better quilt No sniveler, 270g of down. temp confort +5°C/0°C by experience. this one can convert in upper boddy insulated cloth for camp.
- I'm testing VBLs at the moment. I have tested last week a VBL liner made with a survival blanket (light one 60g). I was extremely convinced by it altough the material was too noisy. This coming weekend, I'll try the VBL but this time made out of plastic bags (hoping that the temperature will drop below 0° but I doubt it) and if I'm still convinced by the experience, I will make myselft a VBL liner with hood and drawcord for this winter with Silnylon. (Also maybe a VBL shirt and pants)
- I also have a down pants and down vest and all of that should keep me confortably warm until -15° -20°.
For lower temperature (-30°C), anyway, you'll need a fire for the camp, otherwise, the camping experience will be difficult. Just the unpacking/packing will be awful.
I have only experienced such low temperature once, but I believe that with a fleece cover (~350g), a fleece pants, thermal pants, and additional fleece sweater, plus jacket and rainpants (or equivalent VBL), I should be alright.
At least, during my experience in -31°C in Oulu at the end of January 2006, I had a similar system and I was rather alright. Not super super confortable, but more OK than very cold.
I'll try to detail a bit more with the following:
[old experience => what I would do now]
- Joutsen 900 QTM => still using the same
- old cheap McKinley synthetic -5°C bag (actually +2°/0°C bag by experience) => now replaced by JackRBetter quilt
- fleece blanket=> I might take a similar one if temperature is really cold (5€/9€ is department stores) => I don't know if I would put it inside my bags (maybe warmer) or outside (would make the 0°C equilibrium point a bit further from body... which would help to keep bags a bit drier but here again, if I use VBL.... ?!)
- moisture was prevented by using synthetic bag outside the downbag => now I would use VBL, so I think it would be OK to use 2 downbags.
- I was wearing thermal bottom clothes (fleece), hiking pants, skipants, and 1 paire of normal socks and 2 pairs of woold grandma-socks (loose) => I replace ski pants by VPL pants and fleece loose pants (both home-made). I keep thermal bottoms and hiking pants and keep the same system for feet + my home made VBL socks which I finished last week.
- I was wearing thermal upper body cloth (synthetic), fleece sweather, wool sweather with synthetic insulation, and hiking jacket => I would use the same thermal cloth and fleece sweater. I'm adding my merino shirt, VBL shirt (homemade), my down vest, and maybe a light wool shirt (if I fear for extreme cold).
- gloves => Of coure, I would wear them
- for the head system, since I would loose one hood (quilt instead of synthetic bag), I would add more beanie / balaclava.
last thought, in opposite with Roger, I think that your mattress system is too weak.
For such low temperature, I had a 3cm thick foam pad from K-market (bought I was living in Kajaani) and 2 half-length torso foam pads (old Millet pads, 8mm x2).=> now, I think I would use my full length foam mat "CAMP'INN bioeva" (~8mm) + 2/3 ridgrest rolled together tight (a bit bulky but 20cm of diameter rolled, and carried outside the backpack) and my Prolite 3 + windscreen sun protection for car rolled inside my backpack.
And also, I think your head insulation is also too weak, since you only have your downjacket hood for it if you use 2 quilts. You'll have to review that.
My list is far from being a "dreamlist". I'm using what I currently have and some other cheap things. It could be perfected, but unfortunately, I don't have much money for it at the moment.
But despite all, I know it works or would work by those temperatures in the south of Finland.
It seems a lot, presented like that, but I can store all of that in my ULA conduit for a 2/3 days hiking trip. For a 5 days or week long trip, I would use probably all my mesh pockets and probably a front "belly"bag (I don't know how do you call them in english). but I believe that a bigger pack would be definitely more appropriate.
A yeah... last, but not least, I would take a very small shelter (such as the gatewood cape) in the south of Finland. => Lots of trees and usually very stable weather conditions, so not need for a bombproof shelter!
In the case of a trip to the northern part of Finland for example (Lapland, above the treeline), I would at least take the outside of my Hilleberg Unna, and maybe even the inside. but in this case, I would loose a lot of space in my pack, and I would therefore need a much bigger pack (something equivalent to cuircuit or even catalyst).
Ok. Long post... I hope you didn't fall asleep. :D
I don't pretend this is the perfect list, but it would be my list for such a trip, and I have faith in it.
But it is like everything, it's not a definite list, but rather an ever changing experience!
We could discuss more about it in the near feature on a camping trip.
See you soon.
'Hope that it helps.